Succeeding with Behavior Driven Development (BDD)

Succeeding with Behavior Driven
Development (BDD) Testing and
Automation
Seattle Area Software Quality Assurance Group
Oct 18, 2012
Alan Myrvold
Google
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About me
Feb 2011 - now
Google
Test Engineer, Ads
2005 - 2011
Microsoft
SDET in Office Security + Outlook
1998 - 2005
Entrust
Test manager, development manager,
security assurance manager
1988 - 1998
Cognos
Tester, developer, test manager,
development manager
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More about me
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Buzzword bingo
ATDD
BDD
Cucumber
Cucumber - JVM
Gherkin
Jasmine
SpecFlow
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Buzzword bingo
ATDD
- acceptance test driven development
BDD
- behavior driven development
Cucumber
- a Ruby tool that supports BDD
Cucumber - JVM
- a Java tool that supports BDD
Gherkin
- the language used by Cucumber
Jasmine
- a javascript tool for BDD
SpecFlow
- a .NET tool for BDD
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Cucumber Example
Feature: Addition
In order to avoid silly mistakes
As a math idiot
I want to be told the sum of two numbers
Scenario: Add two numbers
Given I have entered 50 into the calculator
And I have entered 70 into the calculator
When I press add
Then the result should be 120 on the screen
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Given / When / Then
Given - precondition
When - action
Then - assertion on expected result
And - same action as before
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Cucumber step implementation
@When("I have entered (.*) into the calculator")
public void enterNumber(int number) {
...
}
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Scenario Outline Example
Scenario Outline: Add two numbers
Given I have entered <x> into the calculator
And I have entered <y> into the calculator
When I press add
Then the result should be <z> on the screen
Examples:
| x | y
| 2 | 3
| 0 | -1
| z
| 5
| -1
|
|
|
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Why BDD?
Clarifying requirements by example
Demystifying automated tests by using English
Demystifying repeated manual tests by emphasizing why
and what to verify.
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Some test types
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How I used BDD at Microsoft
Clarifying requirements in my test plan.
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How we are using BDD at Google
My group, DoubleClick Bid Manager, uses BDD for Java API-level
system tests and repeated manual tests.
Other groups use BDD tests for Java WebDriver tests.
We share the same framework, developed internally.
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Tools support + Books
Tools:
o
Cucumber - Ruby http://cukes.info
o Cucumber JVM
https://github.com/cucumber/cucumber-jvm
o SpecFlow - Binding business requirements to .NET code
http://specflow.org
Books
o
The Cucumber Book
o The RSpec Book
o Cucumber Recipies (beta, scheduled 3/7/2013)
All books from Pragmatic Programmers, http://pragprog.com
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When / Then elsewhere
Mockito … a Java unit testing framework
@Mock CalculationEngine engine;
Calculator calculator = new Calculator(engine);
when(engine.add(2, 2)).thenReturn(4);
calculator.parse("2 + 2 =");
assertEquals("4", caclulator.getResult());
Compare the syntax to EasyMock:
expect(engine.add(2, 2)).andReturn(4);
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describe / it
Rspec … a Ruby unit testing framework
describe Calculator, "#basics" do
it "return 4 for 2+2" do
calc = Caculator.new
calc.add(2, 2)
calc.result.should eq(4)
end
end
Jasmine … a Javascript unit testing framework
describe("calc", function() {
it("2+2 is 4", function() {
expect(calc(2, 2).toEqual(4);
});
});
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Failure mode #1 - Too implementation dependent
BAD
BETTER
Given I have entered 50
into the calculator
And I have entered 70 into
the calculator
When I press add
Then the result should be
120 on the screen
When I add 50 and 70
Then the result is 120
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Failure mode #2 - Programmatic Scripts
BAD
BETTER
When I set x to 1
And while x < 50
And set row x to "empty"
Then set the first 50 rows to
"empty"
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Failure mode #3 - Too low level
BAD
BETTER
When I go to the login page
And enter "bob" into the
username field
And enter "pass123" into
the password field
And click login
Then I am logged in as
"bob"
When I log in as "bob"
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Failure mode #4 - Not exploring interesting cases
BAD
BETTER
When I add 50 and 70
Then the result is 120
When I add 50 and 70
Then the result is 120
When I add 1e90, 0.1, and -1e90
Then the result is 0.1
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Failure mode #5 - Not using regex
BAD
BETTER
@When("Set the budget to
100")
public void setBudget()
{
...
}
@When("Set the budget to (.*)")
public void setBudget(int
amount)
{
...
}
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Failure mode #6 - Complex parsing logic
BAD
BETTER
@When("(.*) the (.*) to
(.*)")
public void doAction(String
action, String name,
String value)
{
if (action.equals("set")
&& name.equals("budget")
}
@When("Set the budget to (.*)")
public void setBudget(int
amount)
{
...
}
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Failure mode #7 - Leaking code details
BAD
BETTER
When I click the BTNREFRESH-ALL button
When I refresh all
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Failure mode #8 - Bad test architecture
BAD
BETTER
Calling entry points in
code that are fragile,
or disappear
Using supported public or test
API's
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Success tips from me
Use BDD for a small set of tests
Focus on human readability, as a domain expert using the feature
would describe a test
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Success tips from The Cucumber Book, by Matt
Wayne and Aslak Hellesoy
DAMP beats DRY
DAMP: Descriptive and meaningful phrases
DRY: Don’t repeat yourself
Declarative better than imperative
Declarative: Given I am logged in
Imperative: Log in as user “Bob”
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Questions?
http://testapprentice.com
[email protected]
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